<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../../js/jquery-3.4.1.js"></script>
</head>
<body>
<select id="sel1" onchange="changeFunc1()">
    <option value="1">s1</option>
    <option value="2" selected="selected">s2</option>
    <option value="3">s3</option>
</select>
<script type="text/javascript">

    $(function () {
        /*$('#sel1').change(function () {
            console.log("change event");
        });*/
        // 手动触发对应的事件
        $('#sel1').change();
    })

    function changeFunc1() {
        console.log("change event 1")
    }

</script>
</body>
</html>